/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.query.udf.example;

import org.apache.iotdb.tsfile.exception.write.UnSupportedDataTypeException;
import org.apache.iotdb.udf.api.UDTF;
import org.apache.iotdb.udf.api.access.Row;
import org.apache.iotdb.udf.api.collector.PointCollector;
import org.apache.iotdb.udf.api.customizer.config.UDTFConfigurations;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameterValidator;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameters;
import org.apache.iotdb.udf.api.customizer.strategy.RowByRowAccessStrategy;
import org.apache.iotdb.udf.api.type.Type;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

public class Adder implements UDTF {

    private static final Logger logger = LoggerFactory.getLogger(Adder.class);

    private double addend;

    @Override
    public void validate(UDFParameterValidator validator) throws Exception {
        validator
                .validateInputSeriesNumber(2)
                .validateInputSeriesDataType(0, Type.INT32, Type.INT64, Type.FLOAT, Type.DOUBLE)
                .validateInputSeriesDataType(1, Type.INT32, Type.INT64, Type.FLOAT, Type.DOUBLE);
    }

    @Override
    public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations) {
        logger.debug("Adder#beforeStart");
        addend = parameters.getFloatOrDefault("addend", 0);
        configurations.setOutputDataType(Type.INT64).setAccessStrategy(new RowByRowAccessStrategy());
    }

    @Override
    public void transform(Row row, PointCollector collector) throws Exception {
        if (row.isNull(0) || row.isNull(1)) {
            return;
        }
        collector.putLong(
                row.getTime(), (long) (extractDoubleValue(row, 0) + extractDoubleValue(row, 1) + addend));
    }

    private double extractDoubleValue(Row row, int index) throws IOException {
        double value;
        switch (row.getDataType(index)) {
            case INT32:
                value = row.getInt(index);
                break;
            case INT64:
                value = (double) row.getLong(index);
                break;
            case FLOAT:
                value = row.getFloat(index);
                break;
            case DOUBLE:
                value = row.getDouble(index);
                break;
            default:
                throw new UnSupportedDataTypeException(row.getDataType(index).toString());
        }
        return value;
    }

    @Override
    public void beforeDestroy() {
        logger.debug("Adder#beforeDestroy");
    }
}
